Locking systems protect objects or information from unauthorised access. A mechanical or electronic lock having a corresponding mechanical or electronic key moves or controls for example a bolt system for locking a door. However, no lock or locking system is absolutely secure. With enough time, criminal energy and technical expenditure, most locks can be “cracked”. Keys are secretly copied, methods for opening without a key are devised, electronic systems are collected by espionage and defeated. For this reason, over time the technologies of locks and locking systems have been repeatedly further developed in order to make criminal access correspondingly more difficult.
Various types of locks or locking systems exist. In the case of a purely mechanical lock, mechanical unlocking for example of a door is achieved by means of a mechanical key. The force for moving the bolt results from the movement of the mechanical key, for example a rotary movement, once the shape of the key in the lock has been checked and corresponding mechanical features match the lock specification and permit the rotary movement. This shape of the lock, for example as a cylinder lock, is widespread.
In the case of an electrical locking system, an electrical or hydraulic operation moves the bolts. The key that fits the lock merely triggers this operation. This may be done by a simple motor control or by appropriate data items, for example to a central location. Frequent applications include so-called transponder locks, in which an electronic key exchanges data with a corresponding electronic lock.
A: mechanical lock
Typically, a mechanical key carries mechanical features that are externally visible and that are correspondingly checked in the lock. If the key and the lock match, locking is permitted, with the result that turning the key can trigger a further mechanical operation.
Advantage of Mechanical Locks:
They are relatively simple to manufacture, and keys may be passed to other persons without problems. Usually, the keys are made of metal and also withstand high temperatures, for example in the event of a fire.
The disadvantage of locks of this kind consists in so-called lock picking, that is to say opening a mechanical lock using corresponding methods and tools. The fact that there are even official championships for this demonstrates the insecurity of locks of this kind. Moreover, mechanical keys are typically easy to copy, since the key's mechanical “information” is openly shown.
A further type of lock is the combination lock, in which entering an appropriate number triggers an opening mechanism.
Disadvantage: passing on the combination “key” is problematic, since the person receiving it may have to note a relatively long sequence of numbers.
Numbers may be forgotten, in particular when there is time pressure.
B: electronic lock:
The key of an electronic lock comprises electronic components that exchange information by radio or optical link when a magnetic card or the key is brought close to the lock, or in the event of manual activation. If access is authorised, a corresponding opening mechanism is then actuated electrically, for example by way of a servo motor.
Advantage of Electronic Lock:
Data may be managed in central processors, for example ideally as a time-recording system. (Electronic) lock picking is difficult or impossible.
Disadvantage of electronic keys: mechanically sensitive, and can easily become faulty. Can be spied on. Does not withstand high temperatures; in the event of a fire an electronic key is typically irreparably destroyed.
The more difficult it is to pick a lock or to copy a key, the more reliable the locking system. In the case of the cylinder locks which are usual today, a key may be reworked within a few minutes without any problems at all by any specialist locksmith or suitable service provider such as are to be found today in many shopping centres. Even high-security keys only provide “higher” levels of security to the extent that they are not (legally) permitted to be reworked by key service providers because of corresponding regulations. From a technical point of view, copying a key of this kind is hardly ever a problem. There is thus only security against forgery because of corresponding agreements. Nowadays, even a photo of a key taken from some distance away is sufficient to make a complete functional copy of the key using a 3D printer.